1. Field of the Invention
The present invention relates to temperature reporting and more particularly to a method and system for reporting outside temperature for display on a mobile station such as a cellular telephone for instance.
2. Description of Related Art
In a typical cellular radio communications system (wireless telecommunications network), an area is divided geographically into a number of cells and, in turn, sectors, each defined by a radio frequency (RF) radiation pattern from a respective base transceiver station (BTS, or “base station”) antenna. The base stations in the cells are in turn coupled to a base station controller (BSC), which is then coupled to a telecommunications switch or gateway, such as a mobile switching center (MSC) for instance. The MSC may then be coupled to a telecommunications network such as the PSTN (public switched telephone network) or the Internet.
When a mobile station (such as a cellular telephone, pager, or appropriately equipped portable computer, for instance) is positioned in a cell, the mobile station communicates via an RF air interface with the BTS antenna of the cell. This air interface communication can occur over control and traffic channels as defined by an accepted protocol.
For instance, in a Code Division Multiple Access (CDMA) system operating according to industry standard IS-2000 (e.g., TIA/EIA Interim Standard IS-2000-5), up to 64 communication channels exist, each distinguished by a unique “Walsh code.” The control channels include a pilot channel defined by Walsh code 0, a sync channel defined by Walsh code 32, and a number of paging channels defined by Walsh codes 1 through 7, as necessary. The traffic channels, in turn, are defined by the remaining Walsh codes (up to 62 in total).
Further, in a CDMA system, each physical sector in a cell is distinguished by a PN offset, which defines a sector-specific part of a pseudo-random number. Communications between a mobile station and the BTS on a given channel, in a given physical sector, and on a given carrier frequency, are encoded using the Walsh code of the channel and the PN offset of the physical sector and are then carried on the carrier frequency. Details of the mechanics involved in this coding and communication are well known to those of ordinary skill in the art and are therefore not described here.
The IS-2000 pilot channel is used for establishing signal timing and conveying signal strength measurements to facilitate handoff between sectors. The pilot channel does not carry messages but rather provides a stream that mobile stations can frequently sample to determine how well they can hear a base station. A mobile station will measure the pilot when it initializes and regularly while it's powered up, whether idle or in a call, in search of the strongest sector.
The sync channel is used to convey system identification and other system-specific information to mobile stations, generally to allow mobile stations to establish communication in the sector. For this reason, the sync channel carries one message, the sync channel message, which contains information such as the system time, code and frame timing, an indication of the PN offset for the selected sector, and a system ID number. When a mobile station first powers-on in a CDMA system, it will search for the strongest pilot and then check the synch channel to find out what PN offset it is using to communicate with the base station.
A paging channel, in turn, may be used to page a mobile station in order to determine whether the mobile station is available to receive a call. Further the paging channels may carry system information and call setup orders to facilitate establishment of calls with the mobile station. For instance, the base station may send a general page message over the paging channel, which can direct a mobile station to switch to a designated traffic channel and to alert a user of an incoming call. Once a mobile station finds a pilot and checks the synch channel, the mobile will quickly switch to the paging channel to be able to receive calls.